1. Field of the Invention
The present invention relates to a vibration compensation camera having a vibration compensation system to correct vibration of an image caused by hand tremor and the like during photography, and, more particularly, to a vibration compensation camera having a self-timer mode or a bulb mode, which prevents excess power consumption by the vibration compensation system when the camera operates in the self-timer mode or a bulb mode.
2. Description of the Related Art
Vibration compensation cameras are known having vibration compensation mechanisms to correct for the effects of vibration caused by hand tremor and the like during photography. The known types of vibration compensation cameras include vibration detection circuits arranged within the camera to detect vibration. When vibration is detected by the vibration detection circuits, a compensation lens arranged as a portion of the photographic lens system is moved during the time that a camera shutter is open, based on the output of the vibration detection circuits. The compensation lens is moved in a direction approximately at right angles to the optical axis to negate the vibration. Further, the known vibration compensation cameras also include various camera accessory mechanisms, such as a self-timer mechanism to effect photography after a predetermined time period has elapsed from a release operation, and a bulb function or bulb mode, which is a known camera setting in which the shutter can be opened by initiating the release operation and closed when the release operation is ended, to maintain an optional time for a shutter open state.
However, in the known type of vibration compensation camera including a self-timer mode and mechanism, the following problems arise. Firstly, when the vibration detection circuits are started at the beginning of a photographic process and operate during the time interval beginning from the release action until a photograph is taken, and the vibration detection circuitry remains in a conductive state during photography in the self-timer mode, the power consumption becomes large. Secondly, when photography is performed in the self-timer mode the probability that vibration will arise is small since the camera is usually fixed, e.g., on a tripod. Thus, it is wasteful to operate the vibration compensation function at such a time. Thirdly, when the vibration compensation function is not operated, the vibration compensation lens remains housed at its initial position, and thus is in a position displaced from the center of the optical axis. As a result of the position of the vibration compensation lens, the photographic result becomes inferior.
Further, although it is usually wasteful to start the Vibration detection circuits before necessary because their electric current consumption is large, the vibration detection circuits are not stable until a given time has elapsed after an electrical power source is applied. The vibration detection circuits also have the characteristic that normally a signal cannot be output until the circuits are stable. Because the time necessary until these circuits stabilize is generally 1-2 seconds, the vibration detection circuits start when the half-depression switch is set ON such that the vibration detection circuits are stable when the photographic process commences.
However, in the known vibration compensation camera including a self-timer mode, for the vibration detection circuits to start at the time of commencement of the photographic process during photography in the self-timer mode, the vibration detection circuits remain in a conductive state during the interval from the release operation until photography is carried out. As a result, the electric current consumption of the camera is large.
Further, in the known vibration compensation camera having a bulb mode to maintain an optional time for a shutter open state, when a vibration compensation process is performed in the bulb mode, the motor circuits which drive the vibration compensation lens remain in a conductive state for a long time, such that the electric current consumption of the camera becomes large, and excessive heat is generated by the motor circuits.
Still further, when the vibration compensation function does not operate, the vibration compensation mechanism is housed at an initial position at the end portion of its drive range, and is displaced from the optical axis center. The compensation lens is initially located at this position (1) to maintain the stroke amount during driving of the vibration compensation lens; (2) because lens position detection circuits detect only the amount of movement of the compensation lens, and (3) placing the compensation lens at the end portion of its drive range stabilizes the compensation lens.
Accordingly, when the vibration compensation process is not performed when in the bulb mode, the compensation lens becomes housed at the end portion of its movement range, and, as a result, the compensation lens is maintained in a state which is displaced from the center of the optical axis. Moreover, when performing optical system adjustment to set the positions of the optical system and film surface, shutter opening is performed in the bulb mode; however, a problem arises in that at this time the compensation lens is displaced from the optical axis, and the adjustment of the optical system cannot be accurately performed.